Dietary Energy Levels Research Articles

Effect of dietary energy levels on productivity, fat deposition, and biochemical parameters of Woorimatdag1 breeder pullets.

This study aimed to investigate effects of apparent metabolizable energy (AMEn) levels in diets on productivity, fat deposition, and biochemical parameters of Woorimatdag1 (WMD1) breeder pullets. A total of 240 four-week-old WMD1 breeder pullets were divided into four dietary groups with five replicates (12 birds per replicate). These groups had the following dietary energy levels: standard ME (SME), SME-200, SME-100, and SME+100 (diets containing 2,800, 2,600, 2,700, and 2,900 kcal AMEn/kg, respectively). These pullets were provided with diets and water ad libitum until 16 weeks old. Weight gain was significantly (p < 0.05) higher in SME-100, SME, and SME+100 groups than in the SME-200 group. SME+100 and SME groups exhibited significantly (p < 0.05) improved feed conversion ratio compared to the SME-200 group. Laying ages of 30% egg production occurred significantly (p < 0.05) earlier in SME-100, SME, and SME+100 groups than in the SME-200 group. SME and SME+100 groups had significantly (p < 0.05) higher liver fat (%) than the SME-200 group. Additionally, the SME+100 group had higher (p < 0.05) abdominal fat (%) than other groups. However, blood parameters were not significantly different among dietary groups. SME-100 (2,700 kcal AMEn/kg) might be suitable for improving productivity and fat deposition of WMD1 breeder pullets.

Effects of dietary metabolizable energy and crude protein levels on laying performance, egg quality and fecal microbiota of Taihe Silky Fowl during the peak laying period.

The experiment aimed to study the effect of dietary metabolizable energy (ME) and crude protein (CP) on laying performance, egg quality, serum routine biochemical and lipid metabolism indicators, the apparent digestibility of nutrients, and fecal microbiota of Taihe Silky Fowl (TSF) during the peak laying period. A total of 540 26-week-old TSF female fowls were randomly allocated to 9 groups with 5 replicates per group and 12 fowls per replicate. The fowls were fed with a 3 × 3 factorial arrangement of treatments diets (ME:10.88,11.30, or 11.72 MJ/kg; CP: 15, 16, or 17%). With the increasing CP level, the egg weight (EW) (P=0.023), egg production (EP) (p=0.047), and egg mass (EM) (p=0.022) enhanced, while the feed conversion rate (FCR) (p=0.023) decreased. As the ME levels grew, the average daily feed intake (ADFI) (p<0.001) and FCR (p=0.045) decreased. With enhanced ME, the triglycerides (TG) (p=0.037), total cholesterol (TCHO) (p=0.041), and high-density lipoprotein cholesterol (HDL-C) (p=0.028) increased, whereas the low-density serum lipoprotein cholesterol (LDL-C) (p=0.039) decreased. The apparent digestibility of crude protein increased as the ME level increased (p= 0.029) and as the CP level decreased (p=0.027). At the same time, the apparent digestibility of gross energy increased as the ME level increased (p=0.018). Different levels of ME or CP changed the composition of fecal microbiota, 17% CP increased the abundance of Bifidobacterium. It is suggested that 10.88 MJ/kg dietary ME and 17% CP level are suitable for the nutritional requirements of TSF during the peak laying period.

Lysophospholipid Supplementation in Broiler Breeders’ Diet Benefits Offspring’s Productive Performance, Blood Parameters, and Hepatic β-Oxidation Genes

The present study aimed to investigate whether supplementation of modified lysophospholipids (LPLs) in the diet of broiler breeders can benefit their offspring. A total of 264 49-week-old breeders (Ross 308) were allocated and fed based on a 2 × 2 factorial arrangement with two levels of dietary energy (normal energy = 2800 kcal/kg and low energy = 2760 kcal/kg) and two LPL levels (0 and 0.5 g/kg) for periods of 8 and 12 weeks. The offspring were assessed for growth performance, serum parameters, hepatic antioxidative capability, and expression of genes involved in liver β-oxidation at 7 days old. The LPL inclusion improved (p &lt; 0.01) average body weight (ABW), average daily gain (ADG), and feed conversion ratio (FCR). The offspring of 61-week-old breeders fed with LPL exhibited reduced serum triglyceride levels (p &lt; 0.01) but an increase in hepatic glutathione peroxidase (p &lt; 0.05). The LPL increased (p &lt; 0.001) the mRNA expression of the PGC-1α gene in the liver. Supplementing LPL in low-energy diets resulted in higher FABP1 gene expression (p &lt; 0.05) in the intestine. In conclusion, LPL supplementation in the breeders’ diet improved offspring performance by enhancing fatty acid absorption, hepatic indices, and the expression of genes involved in liver β-oxidation.

Effect of different Energy and Protein levels in Hubbard broiler diet on Expression of some growth-related genes and Intestinal Morphology

Effect of different Energy and Protein levels in Hubbard broiler diet on Expression of some growth-related genes and Intestinal Morphology

Effect of different Energy and Protein levels in Hubbard broiler diet on growth performance and some related blood metabolic parameters

Effect of different Energy and Protein levels in Hubbard broiler diet on growth performance and some related blood metabolic parameters

Growth and Laying Performance of Local Guinea Fowl on Different Dietary Protein and Energy Levels

Constraints to Guinea fowl (Numida meleagris) production include poor growth and low laying performance. However, the lack of standard nutritional requirements significantly hinders commercial indigenous Guinea fowl production in Nigeria. This study aimed to determine the proper levels of crude protein (14, 16, and 18%) and metabolizable energy (2.65, 2.75, and 2.85 Mcal/kg) in the diets of native Guinea fowl in Nigeria. The dietary protein (PL) and energy (EL) levels for the fowl were evaluated in a completely randomized 3 (PL) × 3 (EL) factorial design with three replicates of 10 birds each. Thus, 270 birds with 20 weeks of age were allocated randomly to nine dietary treatments (18P:2.65E, 18P:2.75E, 18P:2.85E, 16P:2.65E, 16P:2.75E, 16P:2.85E, 14P:2.65E, 14P:2.75E and 14P:2.85E). The PL × EL interaction affected Guinea fowl's DFI, DWG, and WWG (p&amp;lt;0.05), while WFI and FCR remained unaffected. The 16:2.85E diet increased the DFI of the birds compared to other diets (p˂0.05). The DFI of the 18:2.65, 18:2.75, and 16:2.75E Guinea fowls was higher than those of 18:2.85E, 14:2.65E, 14:2.75E, and 14:2.85 birds (p˂0.05). The DWG of fowls improved by the 16:2.85E diet compared to other diets, except for the 18P:2.65E and 16P:2.75E diets (p˂0.05). The interaction had a significant impact on the EN, EYH, and EM of the Guinea fowl egg while FCR remained unaffected. The 18P:2.85E diet improved the EN and EM of the birds compared to other diets (p˂0.05), The 18P:2.85E also improved the FCR for laying except for 14P:2.85E and 18P:2.75E. The 18P:2.85E diet influenced the YW of the birds compared to other diets (p˂0.05), whereas the EW of fowls improved by the 16:2.85E diet compared to other diets except for the 16P:2.65E diet (p˂0.05). In conclusion, feeding guinea fowls with a diet comprising 18% protein and 2.85 Mcal/kg metabolizable energy significantly improved egg production and quality.

Dietary metabolizable energy and crude protein levels affect Taihe silky fowl growth performance, meat quality, and cecal microbiota during fattening

The effects of dietary metabolizable energy (ME) and crude protein (CP) on the growth performance, meat quality, and cecal microbiota of Taihe Silky Fowl (TSF) during fattening were investigated. In total, 900 twelve-week-old female fowl were randomly allocated to 9 treatments (5 replicates per group, 20 fowl per replicate), and were fed a 3 × 3 factorial arrangement of treatments diets (ME: 11.30, 11.93, or 12.56 MJ/kg; CP: 15%, 16%, or 17%). As ME increased, the average daily feed intake (ADFI, P<0.001), feed conversion ratio (FCR, P<0.001), pectoral and thigh shear forces (P<0.05), pectoral and thigh muscle fiber diameter (P<0.001) decreased significantly, while muscle fiber density increased (P<0.001). Pectoral muscle fiber diameter was lower and muscle fiber density higher at 16% CP than 15% or 17%. As ME increased, pectoral crude fat content increased significantly (P = 0.007). Pectoral crude protein, total amino acid (TAA), and essential amino acid (EAA) content were higher at 15% dietary CP than 16% or 17%. As ME increased, pectoral inosine monophosphate (IMP, P = 0.006), uridylic monophosphate (UMP, P = 0.003), guanylic monophosphate (GMP, P = 0.009), and adenosine monophosphate (AMP, P <0.001) decreased significantly, while hypoxanthine riboside (HxR, P = 0.045) increased. As dietary CP increased, IMP (P = 0.019), AMP (P <0.001), and HxR (P = 0.024) increased significantly. Cecal microbiota composition varied with dietary ME: 12.56 MJ/kg ME increased the abundance of Bifidobacteriaceae, and 15% CP increased that of Paraprevotella. These findings suggest that 12.56 MJ/kg dietary ME and 15% CP can enhance growth performance, improve meat quality by reducing shear force, enhancing flavor and nutritional value, and benefit for intestinal microbiota in fattening TSF.

Interactive effects of dietary energy levels with amino acid density on growth performance and optimal digestible Lys to energy ratio of male broiler chickens

A total of 2,400 day-old off-sex male Ross 308 chicks were used in a 4 × 3 factorial array (8 replicates with 25 birds per replicate) to determine the interactive effects of dietary metabolizable energy (ME) and amino acid (AA) densities on productive traits of broiler chickens reared to 42 d of age. The experimental factors were 4 ME levels (control, -50, -100, -150 kcal) and 3 digestible AA levels (control, +3.0 and +6.0%). Diets were fed for starter (0-10 d), grower (11-24 d), finisher (25-35 d), and withdrawal (36-42 d) phases, with consistent reduction of ME and increase in AA density for each phase. Overall, ME reduction did not compromise final body weight (BW; d 42). However, when ME was reduced by 50 kcal, only the diets with +6% AA density improved BW, resulting in an interaction between ME and AA levels (P < 0.05). Reducing ME and increasing AA densities independently increased total feed intake (P < 0.01). An interaction between ME and AA density on feed conversion ratio (FCR) was observed where increasing AA density at both +3.0 and +6.0% levels at control ME reduced FCR, but with reduced ME diets, FCR was reduced only at +6% AA density (P < 0.01). Quadratic broken line models estimated a digestible Lys to ME ratio (mg Lys/1,000 kcal ME) of 474 and 407 in starter and grower diets, respectively, to optimize both BW and FCR. However, in finisher phase a ratio of 363 could only be predicted for optimal FCR and in withdrawal a ratio of 349 to optimize BW. In summary, these results indicate that the interaction between ME and AA densities affects the productive traits of broiler chickens. Increasing AA density at control ME density improves FCR, while reduced ME diets require higher AA density to improve FCR. Quadratic broken line models suggest specific digestible Lys to ME ratios for optimizing BW and FCR across different phases of the production cycle.

Effects of Dietary Energy Levels on Growth Performance, Nutrient Digestibility, Rumen Barrier and Microflora in Sheep.

Dietary energy is crucial for ruminants' performance and health. To determine optimal dietary energy levels for growing sheep, we evaluated their growth performance, nutrient digestibility, rumen fermentation, barrier function, and microbiota under varying metabolic energy (ME) diets. Forty-five growing Yunnan semi-fine wool sheep, aged 10 months and weighing 30.8 ± 1.9 kg, were randomly allocated to five treatments, each receiving diets with ME levels of 8.0, 8.6, 9.2, 9.8 or 10.4 MJ/kg. The results showed that with increasing dietary energy, the average daily gain (ADG) as well as the digestibility of dry matter (DM) and organic matter (OM) increased (p < 0.05), while the feed conversion ratio (FCR) decreased linearly (p = 0.01). The concentration of total VFA (p = 0.03) and propionate (p = 0.01) in the rumen increased linearly, while rumen pH (p < 0.01) and the acetate-propionate ratio (p = 0.01) decreased linearly. Meanwhile, the protein contents of Claudin-4, Claudin-7, Occludin and ZO-1 as well as the relative mRNA expression of Claudin-4 and Occludin also increased (p < 0.05). In addition, rumen bacterial diversity decreased with the increase of dietary energy, and the relative abundance of some bacteria (like Saccharofermentans, Prevotella and Succiniclasticum) changed. In conclusion, increasing dietary energy levels enhanced growth performance, nutrient digestibility, rumen fermentation, and barrier function, and altered the rumen bacterial community distribution. The optimal dietary ME for these parameters in sheep at this growth stage was between 9.8 and 10.4 MJ/kg.

Effects of increasing SID lysine and metabolizable energy levels in lactation diets fed to young and mature sows.

The objective was to evaluate increasing standard ileal digestible (SID) lysine (Lys) and metabolizable energy (ME) above recommended inclusion levels fed to young (parity 1-2) and mature (parity 3-5) lactating sows. A total of 741 sows (371 parity 1-2, 370 parity 3-5) were fed in a 2×2 factorial arrangement of treatments in a randomized complete block design. Factors included SID Lys (0.85% vs 1.11%) and ME (3.18 Mcal/kg vs 3.33 Mcal/kg). Diets were formulated to deliver 62g of SID Lys at 0.85% inclusion and 23.2 Mcal of energy to sows that consume 7.30kg of complete feed per day. Overall, sows consumed 61g/d SID Lys and 22.6 Mcal/kg, but because of nutrient intake differences between young and mature sows, outcome variables were analyzed separately and not statistically compared. There were no differences for either SID Lysine or ME treatment in lactation feed intake (P ≥ 0.27) or change in body weight (P ≥ 0.19) for young sows. Young sows fed 3.33 Mcal/kg ME had 0.31 fewer post-cross foster mortalities (P < 0.01) resulting in weaned litters that were 4.06kg heavier (P < 0.01) than litters from young sows fed 3.18 Mcal/kg ME. Young sows fed 1.11% SID Lys and 3.33 Mcal/kg ME had the fewest (P ≤ 0.03) sows bred by d 7 compared to all other treatments. There was an interaction (P = 0.03) for wean-to-estrus-interval for young sows were young sows fed 1.11% SID Lys and 3.33 Mcal/kg ME were at least 3.27 days longer than young sows fed 0.85% SID Lys and 3.33 Mcal/kg ME or 1.11% SID Lys and 3.18 Mcal/kg ME. Young sows fed 3.33 Mcal/kg ME had a nearly 7% improvement in lactation G:F (0.40 vs 0.43; P < 0.01) compared to young sows fed 3.18 Mcal/kg ME. The percentage of mature sows fed 1.11% SID Lys bred by day 7 was 7.0 percentage units less (P = 0.06) when fed 3.33 Mcal/kg ME compared to 3.18 Mcal/kg ME. Feed efficiency of mature sows fed 1.11% SID Lys (0.38) was 7.89% greater (P < 0.01) than mature sows fed 0.85% SID Lys (0.35). Increasing either SID Lys or ME energy to young and mature sows had little influence on sow or pig performance, but simultaneously increasing both SID Lys and metabolizable energy negatively impacted subsequent breeding performance.

Effect of Dietary Energy Level during Late Gestation on Mineral Contents in Colostrum, Milk, and Plasma of Lactating Jennies.

This study investigated the effects of dietary energy levels during late gestation on mineral content in the plasma, colostrum, and milk of jennies postpartum. Twenty-four pregnant multiparous DeZhou jennies, aged 6.0 ± 0.1 years, with a body weight of 292 ± 33 kg, an average parity number of 2.7 ± 0.1, and similar expected dates of confinement (74 ± 4 days), were randomly allocated to three groups and fed three diets: high energy (12.54 MJ/kg, HE), medium energy (12.03 MJ/kg, ME), and low energy (11.39 MJ/kg, LE). Blood samples were collected from the jugular vein of each jenny at time points of 0 h, 24 h, 48 h, 5 d, 7 d, and 14 d after parturition. Additionally, milk samples were collected through manual milking, and an analysis of the mineral content was conducted. The results showed that compared with HE, both ME and LE significantly increased the levels of calcium (Ca), phosphorus (P), zinc (Zn), selenium (Se), molybdenum (Mo), and cobalt (Co) in the plasma and Ca, P, magnesium (Mg), copper (Cu), manganese (Mn), Zn, selenium (Se), molybdenum (Mo), and Co in the milk of jennies postpartum (p < 0.05); ME also increased the levels of potassium (K), iron (Fe), and Mn in plasma and K and Fe in milk (p < 0.05). The levels of Ca, K, Mg, P, Fe, Cu, Mn, Co, Se, Zn, and Mo in plasma and milk gradually decreased with increasing postpartum time. Their contents were the highest at 0 h postpartum, rapidly decreased after 24 h postpartum, and declined to the lowest on day 14 postpartum. The interaction between dietary energy level and postpartum time showed that although the concentrations of the minerals Ca, P, K, Mg, Fe, Cu, Mn, Zn, Co, Se, and Mo decreased in jennies' plasma and milk in the treatment groups with different energy levels as postpartum time increased, the pattern of change was also influenced by dietary energy level. The influence of dietary energy level in late gestation on the mineral content of milk and plasma during the postpartum colostrum phase was higher than that during the milk phase. In conclusion, this study demonstrated that, under the current experimental conditions, the mineral content of the colostrum, milk, and plasma of jennies after parturition was dependent on the dietary energy level during late gestation.

Effects of Dietary Energy Levels on Growth Performance, Serum Metabolites, and Meat Quality of Jersey Cattle-Yaks.

Energy feed can provide animals with balanced nutrition, thereby enhancing their growth performance. This study aimed to evaluate the effects of dietary energy levels on the growth performance, serum metabolites, and meat quality of Jersey cattle-yaks. A total of 24 male Jersey cattle-yaks were randomly divided into three groups. Each group was fed diets with metabolizable energy levels of 8.21 MJ/kg (LE), 9.50 MJ/kg (ME), and 10.65 MJ/kg (HE), respectively. The HE and ME groups showed significantly higher final body weight, average daily gain (ADG), and feed efficiency compared to the LE group (p < 0.05). The glucose (GLU) and total cholesterol (TC) concentrations were significantly increased in the serum of the ME and HE groups (p < 0.05). The low-density lipoprotein cholesterol (LDL-C) and alanine aminotransferase (ALT) levels were significantly higher in the serum of the HE group than in the ME group (p < 0.05). Blood urea nitrogen (BUN) levels exhibited a significant decrease with increasing metabolizable energy levels in the diet (p < 0.05). Increasing dietary energy levels enhances the eye muscle area and intramuscular fat content of Jersey cattle-yaks (p < 0.05), with no effect on pH45 min, pH24 h, and shear force. In the HE group, the levels of heneicosanoic acid (C21:0), palmitoleic acid (C16:1), elaidic acid (C18:1n9t), and eicosadienoic acid (C20:2n6) were notably elevated (p < 0.05) when compared to the LE group. We concluded that a higher dietary energy level enhanced the growth performance and meat quality traits of male Jersey cattle-yaks.

The influence of breed, dietary energy and lysine on laying persistency and body composition of laying hens

The effect of dietary energy and lysine levels on laying persistency and body composition in brown and white hens was studied. Dietary treatments with 2 Metabolizable Energy levels (ME lay; constant or reduction over time) and 2 apparent fecal digestible Lys levels (AFD Lys; constant or reduction over time), were fed to Lohmann white or brown hens, from 17 to 75 wk of age, in a 2 × 2 × 2 factorial design. Data were subjected to mixed model analyses. The egg production curve was modeled using a non-linear regression function. White hens showed an improved laying persistency and a higher number of total eggs per hen compared to brown hens, indicated by a shorter peak production phase but a significant lower slope of decline after peak (P < 0.05). Similarly, hensfed a reduced instead of a constant ME Lay diet had a better laying persistency, indicated by a shorter peak production phase and a significant smaller slope of decline after peak (P < 0.05). This improved laying persistency was probably related to a higher ADFI and nutrient intake of hens fed the reduced ME Lay diets (P < 0.05). A segmented regression analysis showed reasonable correlation between egg mass production and ME Lay intake, with an R2 adjusted of 0.78 for the overall model. The egg mass production was not increased for intakes above 330 kcal of ME Lay intake for white hens and 324 kcal for brown hens. Limited effects of dietary treatments on body crude fat and crude protein were found. Both energy and protein requirement seemed to increase over time, indicated by higher voluntary nutrient intake and a reducing body crude fat after wk 43 in all treatments. The egg mass production correlated poorly with the AFD Lys intake, with an R2 of 0.22. In conclusion, laying persistency was mostly influenced by breed and dietary ME Lay level, but not dietary AFD Lys level.

Dietary Energy and Protein Levels Influence the Mutton Quality and Metabolomic Profile of the Yunshang Black Goat.

This study aimed to evaluate the impact of dietary energy and protein levels on the meat quality and metabolomic profile of Yunshang black goats. For this, 80 Yunshang black goats (male, 6 months old, with a mean live body weight of 35.82 ± 2.79 kg) were used in a completely randomized design with a 2 × 2 factorial dietary arrangement. The dietary treatments were (1) high energy (9.74 MJ/kg) with high protein (12.99%) (HEHP), (2) high energy (9.76 MJ/kg) with low protein (10.01%) (HELP), (3) low energy (8.18 MJ/kg) with high protein (13.04%) (LEHP), and (4) low energy (8.14 MJ/kg) with low protein (10.05%) (LELP). The experiment lasted 64 days, including 14 days for dietary adaptation and a 50-day feeding trial. At the end of the experiment, four animals from each treatment were slaughtered to assess their meat quality and metabolomic profiles. The pH value was greater for the goats fed the LELP diet compared with the other treatments. The LEHP-fed group's meat was brighter (L*) than that of the other three groups. The HEHP-fed group had considerably more tender meat (p < 0.05) compared with the LEHP-fed group. Moreover, 72 and 183 differentiated metabolites were detected in the longissimus muscle samples by using gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry, respectively. The hydropathy and volatilities of raw meat were different (p < 0.05), suggesting changes in the meat flavor because of the dietary treatments. Based on the results, it can be concluded that feeding a high-energy- and high-protein-containing diet improved the tenderness, flavor, and fatty acid contents of mutton.

Effects of different energy levels in low-protein diet on liver lipid metabolism in the late-phase laying hens through the gut-liver axis

BackgroundThe energy/protein imbalance in a low-protein diet induces lipid metabolism disorders in late-phase laying hens. Reducing energy levels in the low-protein diet to adjust the energy-to-protein ratio may improve fat deposition, but this also decreases the laying performance of hens. This study investigated the mechanism by which different energy levels in the low-protein diet influences liver lipid metabolism in late-phase laying hens through the enterohepatic axis to guide feed optimization and nutrition strategies. A total of 288 laying hens were randomly allocated to the normal-energy and normal-protein diet group (positive control: CK) or 1 of 3 groups: low-energy and low-protein diet (LL), normal-energy and low-protein diet (NL), and high-energy and low-protein diet (HL) groups. The energy-to-protein ratios of the CK, LL, NL, and HL diets were 0.67, 0.74, 0.77, and 0.80, respectively.ResultsCompared with the CK group, egg quality deteriorated with increasing energy intake in late-phase laying hens fed low-protein diet. Hens fed LL, NL, and HL diets had significantly higher triglyceride, total cholesterol, acetyl-CoA carboxylase, and fatty acid synthase levels, but significantly lower hepatic lipase levels compared with the CK group. Liver transcriptome sequencing revealed that genes involved in fatty acid beta-oxidation (ACOX1, HADHA, EHHADH, and ACAA1) were downregulated, whereas genes related to fatty acid synthesis (SCD, FASN, and ACACA) were upregulated in LL group compared with the CK group. Comparison of the cecal microbiome showed that in hens fed an LL diet, Lactobacillus and Desulfovibrio were enriched, whereas riboflavin metabolism was suppressed. Cecal metabolites that were most significantly affected by the LL diet included several vitamins, such as riboflavin (vitamin B2), pantethine (vitamin B5 derivative), pyridoxine (vitamin B6), and 4-pyridoxic acid.ConclusionA lipid metabolism disorder due to deficiencies of vitamin B2 and pantethine originating from the metabolism of the cecal microbiome may be the underlying reason for fat accumulation in the liver of late-phase laying hens fed an LL diet. Based on the present study, we propose that targeting vitamin B2 and pantethine (vitamin B5 derivative) might be an effective strategy for improving lipid metabolism in late-phase laying hens fed a low-protein diet.

Effects of finisher diet nutrients density and slaughter age on energy and protein efficiency, productive and economic performance and meat quality of broilers.

The current broilers have been greatly optimized for weight gain and breast yield, which necessitates the provision of nutrients-dense diets for maximum potential. The current study aimed to evaluate the effect of finisher diet nutrients density (ND) on energy and protein efficiency, productive and economic performance and breast meat quality of broilers raised until different slaughter age. A total of 600 23-day-old broiler male chicks (Cobb-500) were assigned to 10 treatments with six replicates and 10 birds each. Experimental treatments were included factorial arrangement of five increment (2.5%) levels of finisher diet ND (92.5%, 95%, 97.5%, 100% and 102.5% as strain recommendation) and slaughtered at 38 or 46 days of age. The relative difference in the energy level of experimental diets was used to increase ND levels at the same ratio. Feed intake (FI) and breast meat quality traits exception water holding capacity (WHC) were not affected by finisher diet ND. In response to increasing finisher diet ND, energy and protein efficiency, productive traits, bio-economic index (BEI) and breast relative weight (BRW) linearly improved. However, residual feed intake and breast meat WHC improved with a quadratic trend. By using broken-line regression analysis, the optimum dietary ND was obtained at 97.5%-102% of strain recommendation. Energy and protein efficiency, feed conversion ratio and BEI deteriorated by prolonging rearing period. The BRW, meat lightness (L*), redness (a*), hue angle (h*) and WHC values for the birds slaughtered at 46 days of age were significantly higher, and cooking loss was lower than those slaughtered at 38 days old. Broilers during the finisher period are not able to regulate their FIs with diet ND. The energy and protein efficiency, productive and economic performance were reduced when broilers were fed diluted diet or the rearing period was prolonged.

Effects of daily consumption of Chinese chicken soup on energy and macronutrients intake

Through various media, people have become increasingly aware of the importance of maintaining a healthy diet, with Cantonese soup, especially chicken soup, emerging as a popular choice due to its comforting and potentially medicinal properties. Chicken soup is valued not only for its rich protein and essential vitamins but also for its hydration benefits and the possibility of easing symptoms of respiratory infections through its anti-inflammatory effects. Despite its recognized health benefits, the specific impact of daily consumption of Cantonese chicken soup on energy levels and nutrient intake remains understudied, prompting further research into its effects on high school students' dietary health. In this three-week randomized controlled trial, sixteen participants including 6 girls and 10 boys from the same high school (mean age 16 years) were included in the analysis. Dietary information, energy levels, and nutrient intakes were gathered using two ASA 24 questionnaires, with the calculations performed by ASA24. Independent samples t-tests and chi square tests were used to compare continuous and categorical variables between the intervention group and the control group, respectively. Paired t-tests were performed to compare pre- and post-ASA24 responses in total energy and macronutrient intakes. Daily consumption of Chinese chicken soup does not seem to improve total energy intake, but it significantly increased % total energy intake from carbohydrates (p&lt;0.05). Further studies with a larger sample size are warranted to confirm the finding.

WPŁYW ZRÓZNICOWANEJ ZAWARTO ˙ SCI BIAŁKA I MOCZNIKA W MLEKU, JAKO BIOMERKERÓW ´ ENERGETYCZNO-BIAŁKOWEGO ZBILANSOWANIA DAWEK POKARMOWYCH, NA POZIOM WYBRANYCH CECH UZYTKOWO ˙ SCI MLECZNEJ KRÓW RASY POLSKIEJ ´ HOLSZTYNSKO-FRYZYJSKIEJ

The aim of the study was to assess the impact of varied levels of milk protein and urea content on selected milk production traits of Polish Holstein-Friesian cows. The research included 34,397 data sets related to daily milk production of Polish Holstein-Friesian cows. These animals were kept in 15 cattle herds located in the Mazovian and Podlasie voivodeships. In the first stage of the research, the animals were differentiated based on the level of urea in their milk and the percentage of protein. According to the adopted assumptions, the energy and protein balance level of feed rations was determined based on the concentration of urea and protein in the milk. Due to the level of urea, three cow groups were distinguished: &lt;150, 150–250, and &gt;250 mg · L-1. Depending on the concentration of protein in the milk, the following three groups of animals were determined: &lt;3.2%, 3.2–3.6%, and &gt;3.6%. The assessment of the impact of varied energy and protein balance levels in feed rations on selected milk production traits of cows was conducted in subsequent lactation periods, production level and fat to protein (F/P) groups. Four lactation periods were distinguished, which covered successive months of lactation: 1–3, 4–6, 7–10, and 11–18, three production groups, determined based on the following levels of daily milk yield: &lt;20, 20–30, and &gt;30 kg and as well three groups of cows with different F/P ratio in milk were distinguished: &lt;1.2, 1.2–1.6, &gt;1.6. In the next stage of the study, a detailed assessment was conducted on the impact of varied levels of energy and protein balance in feed rations on the analyzed milk production traits. The analyzed population of cows was divided into 9 groups based on the level of urea content (mg · L-1) and protein concentration (%), with varying levels of coverage of the protein and energy requirements of cows. The interdependencies between milk performance traits of cows fed diets with balanced levels of energy and protein and their peers, for whom the nutritional diets were differentiated based on energy-protein balance, were determined using Pearson correlation coefficients and linear regression. When assessing the energy supply of cows, the study showed that too low energy levels in diets lead to a decrease in the chemical composition of milk, while too high levels lead to a decrease in milk yield compared to peers fed optimally balanced diets. Milk from cows with inadequate energy and protein nutrition contained less fat and protein by 0.54% and 0.59%, respectively, compared to milk from cows fed optimally. On the other hand, excessive energy supply was accompanied by an increase in fat (+0.66%) and protein (+0.57%) concentration with a decrease in daily milk yield (-4,1 kg). When evaluating the level of protein coverage for cows, the study showed that an excess of protein in feed led to an increase in urea levels in milk. The level of urea in milk from cows fed with excess protein in their feed (&gt;250 mg · L-1 and &lt;3.2%; &gt;250 mg · L-1 and &gt;3.6%; &gt;250 mg · L-1 and 3.2–3.6%) contained more urea per liter compared to milk from cows fed a balanced diet, with increases of 127, 107, and 109 mg, respectively.

Energy and protein levels in dairy cow diets to recover milk ethanol stability

The objective of this study was to evaluate the effect of energy and protein in the diet on the recovery of milk ethanol stability (MES) induced by feed restriction. Twelve Holstein and Holstein x Jersey crossbred cows with an average of 146 ± 50 d in milk, 575.4 ± 70 kg of body weight, and 18.93 ± 5.46 kg/d of milk yield were distributed in a 3x3 Latin square design with 3 treatments and 3 experimental periods. Each experimental period lasted 24 d, comprising 3 phases: a 13-d adaptation phase (100E+100P), a 4-d induction phase for milk ethanol instability (50E+50P), and a 7-d recovery phase for MES (3 treatments). The 3 treatments during the recovery phase consisted of 3 diets aiming to meet the requirements of energy and protein (100E+100P), only energy (100E+50P), or only protein (50E+100P). The diet during the adaptation and induction phases was common for all cows. The energy and protein levels to meet each cow's requirements were based on the group average. Restriction of energy and protein reduced dry matter, crude protein, and total digestive nutrient intake for cows fed 100E+50P and 50E+100P. The lowest body weight was observed for cows fed 50E+100P, with no difference for body condition score. During the induction phase, MES "was" reduced by 9 percentage units. Cows fed 100E+100P recovered MES in the first days of the recovery phase, while 100E+50P slightly improved MES, and 50E+100P had a constant decrease in MES. Cows fed 100E+50P and 50E+100P produced, respectively, 3.6 and 5.9 kg less milk than those fed 100E+100P. The 50E+100P treatment exhibited the highest milk fat content and somatic cell score, along with the lowest milk lactose content. Protein content was higher in the 100E+100P treatment. Cows fed 50E+100P showed higher serum albumin levels compared with those on the 100E+100P treatment, not differing from the 100E+50P treatment. We concluded that the complete recovery of MES in cows with feed restrictions is possible only by supplying both the energy and protein requirements in the cows' diet. However, restricting energy intake poses a greater limitation on MES recovery compared with restricting protein.

Impact of dietary protein and energy levels on fatty acid profile, gut microbiome and cecal metabolome in native growing chickens

The present study investigated the optimal concentration of dietary ME and CP for the fatty acid profile of meat, gut microbiome, and cecal metabolome in Danzhou chickens from 120 to 150 d of age. A total of seven hundred and twenty 120-d-old Danzhou female chickens, with a similar BW, were randomly allocated into 6 treatments with 6 replicates and each of 20 birds. The chickens were fed 2 levels of dietary ME (11.70 MJ/kg, 12.50 MJ/kg), and 3 levels of dietary CP (13%, 14%, and 15%). The results showed that dietary ME and CP levels didn't affect final BW, ADG, ADFI, and feed gain ratio (g: g) (P > 0.05). The serum concentrations of triglyceride, insulin, and glucose in the 12.50 MJ/kg group were the highest (P < 0.05). Dietary ME, CP levels, and their interactions affected (P < 0.05) the fatty acid content in the breast muscle, thigh muscle, and liver. The levels of C18:0, C20:0, C22:0, C22:1, C18:2, C18:3, C22:6, and SFA of the liver in the high ME group were higher than those in the low ME group (P < 0.05). The levels of C16:0, C14:1, C18:1, C22:5, SFA, MUFA and USFA in the low CP group were higher than the corresponding values in the other groups (P < 0.05). Dietary ME and CP levels altered the composition and relative abundance of microbiota in the cecum of chickens at various taxonomic levels to different extents. Significant effects of interactions were found between dietary ME and CP on the relative abundance of 10 species (P < 0.05), and among these species, 6 species belonged to the genus Bacteroides. Notably, the relative abundance of 2 probiotic species including Lactobacillus crispatus and Lactobacillus salivarius was significantly increased (P < 0.05) with increasing dietary ME level. There were 6 differential metabolites in the cecum, comprising thromboxane A2, 5,6-DHET, prostaglandin D2, 20-hydroxyeicosatetraenoic acid, 12(S)-HPETE and prostaglandin I2 significantly reduced (P < 0.05) with increasing the dietary ME level; all of them are involved in arachidonic acid metabolism. In conclusion, the present study suggested that the dietary levels of 12.50 MJ/kg ME and 14% CP enhanced meat quality in terms of fatty acid composition, and showed benefits for maintaining intestinal health via positive regulation of cecal microbiota in native growing Danzhou chickens.